[wip] use yeoman-test

[moritzraho]

Description

yeoman-test provides a convenient framework to test yeoman generators.

changing the current tests to use this framework will allow easily test:

• integration with yeoman run
• outputed files
• options and prompts

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.